The inventive concept relates to semiconductor devices and methods of fabricating semiconductor devices, and more particularly, to methods of fabricating a semiconductor device including a gate electrode filling a trench.
When the channel length of a semiconductor devices, such as a dynamic random access memory (DRAM), is reduced, it is difficult to prevent short channel effects and source/drain punch-through. In addition, an amount of leakage current may be increased, which may reduce the refresh time of a DRAM. To address these problems, recess channel array transistors have been introduced. When a recess channel array transistor is used in a DRAM, cell bit lines and gate electrodes of a peripheral circuit are formed simultaneously. Errors may occur in semiconductor devices due to a step difference between a region where bit-line contact plugs are formed and a region where bit-line contact plugs are not formed.